Primm and Sloan are both NCR territory, so I suspect that some NPC is causing that issue.
Anyways, first of all, get rid of Mission Mojave. That mod "incorporates" a ton of other mods to fix or add things and is, sorry to say it, shit. Plus, it comes with a couple of mods built in, namely the Uncut Wasteland ones, that you've installed on top, so it's no wonder there are issues. And there is Freeside Open in your loadorder. MMUE and that don't play well together unless you create a merged patch and fix the issues yourself, which I don't see in your loadorder, so yet another reason to not use MMUE.
Use YUP instead and get the things that MMUE adds separately. There is literally no reason to not use it and since it's still being updated it's the best patch mod there is. Period.
https://www.nexusmods.com/newvegas/mods/51664
You also should be using the Unofficial Patch Plus. https://www.nexusmods.com/newvegas/mods/62953
That fixes things that YUP ain't touching. Note that you'll need the New Vegas Script Extender and the JIP NVSE plugin for it to work. Heck, you might want to install all of the JIP mods but the selective fire one because they are all great.
Next, Electro City is a questionable lighting choice because it's a bloated mess and can corrupt your saves in the long run. Don't use it. Go with FNV RWL instead.
https://www.nexusmods.com/newvegas/mods/52037/?
If you insist on using FCO and NVR3, follow this article https://www.nexusmods.com/newvegas/articles/55232 to the letter.
Personally I think that Beyond Boulder Dome and New California are overhyped mods of questionable content and value but that's modding for you. Use them, or don't. I wouldn't because the slots they occupy are much better used for better mods...
Also, you need a merged patch. And a bashed patch. Some people might say that this is overkill but that's simply not true. Create a merged patch with FNVEdit (xEdit) and after that create a Bashed patch with Wrye Flash NV.
Personally, for a first time modder I would recommend following the S.T.E.P. guide. Just read all the desciptions for the suggested tools and mods and decide on what you want. It has helpful tips for newbies. https://wiki.step-project.com/User:EssArrBee/FalloutNewVegas#Fallout_Mod_Manager_-_FOMM_-_Fork
And finally, you want Loot, which is linked to in the above mentioned guide. Whenever you are done installing mods and want to test the loadout, run Loot to let it sort your mods. After that, run xEdit to see if it loads without issues. If it stops at any point with an error you'll immediately know what the issue is.
And finally, again

, use Mod Organizer 2. It's simply the best mod manager for FNV and despite a mild learning curve it's superior to literally anything else.